"The Forest of Chakra" (チャクラの森, Chakura no Mori) is episode 10 of the original Naruto anime.

Summary

Kakashi is brought to Tazuna's house to recover from overuse of his Sharingan. When he wakes up, Kakashi realises that Zabuza's death had been odd, and concludes that it had probably been an act. Elsewhere, the hunter-nin, named Haku, revives Zabuza, revealing that he is in league with the missing-nin. Zabuza promises to crush Kakashi when they meet again. In the meantime, both Kakashi and Zabuza need to rest for at least a week to recover from their battle. To prepare for Zabuza's likely return, Kakashi takes Team 7 to the nearby woods for training, where they learn to walk up vertical surfaces using only their chakra. Sakura performs perfectly the first time, but Naruto and Sasuke require extra training. Kakashi notices that Naruto is finally getting a good grasp on teamwork, and recognises that Naruto's chakra is the highest of all those present.